Not 100% sure about isekai-transmigration; if the main character's personality was original, and he discovers a system, or if he's reincarnated in a dead body, reviving it and taking its place, but that also may be possible.
So, it's a cultivation fantasy world; the main character is living in a sect, but is used as toy for draining Qi from, by a woman using an evil cultivation technique. He was going to die soon, but discovers a game-like system, which converts any emotions directed at him into points. He can spend these points to learn and upgrade cultivation techniques, and does so on a very weak technique, which simply grows his life strength and helps him to survive the "draining". Due to this system, he starts to become very provocative to anyone (since he is protected by the same person who drains him as food, for being drained more), and gains more powers. He breaks into a sacred sect chamber, where a great woman was buried, and learns powerful techniques (from the system) for healing most wounds and restoring health, so his status grows.
Also, and most importantly, the system, with enough points, provides temporary transmigration into different worlds and different bodies, with different rules and main missions to complete, for gaining great rewards. One of them was quite similar to our modern world with technology, but also hidden cultivators and spirits. I remember the story quite well, but can't find the manga (manhua) itself, so if anyone has questions about further details, you are welcome to ask.